mrhorsepower1

If you are not changing ANYTHING else in the build except a rotating assembly the factory map should be more than fine. The slight bump in compression and swept cylinder volume will not require a remap. The factory programs are very conservative "rich" . As others have stated prior, cyl.head, camshaft, compression, intake changes ect. then yes a complete remap will be required. The mapping then needs to be based lined with steady state testing on a dyno and final tune I do in the vessel with a wide band.

stevesxm

you are probably correct but " big power" is not the goal here.
the motor starts out at 425 and he was thrilled with that. at first blush, it looks like it might have broken a lifter or run a bump off the cam but i won't really know until i rattle it apart.

i was just thinking that dropping a 540 kit in it/them would buy him some nice low end grunt while it/they were apart. what i do not want to do is have to reinvent the wheel when i am done. as mentioned in the last post, a look at the ports suggests that the map is conservative. that has always been my experience with other factory maps but, as mentioned, i haven't been inside this one so that was just a guess on my part.

ironicly, its going to be the thing that everyone takes for granted as the easiest to do which may keep me from going the 540 route. there are no machine shops here. none...zero. so going this route would mean crating the blocks up and shipping them off miami or maybe puerto rico and dealing with people ive never met who may or may not be any good at what they do. and when the blocks come back and i can put the pistons in sideways ... well then im just screwed.

so... next week ill have it apart and make a decision.

thanks for the insights and suggestions. ill let you know where i go with this.

its the least i can do to provide some entertainment value for you guys as the skys get grey and the cold moves in.

did i mention it was 87 today and you could see the bottom clearly at 25 ft ?

Raylar

SteveSXM:

As for engine and machine service on your little island in the caribean I feel for you, as for the weather conditions you will just have to tuff it out!
Seriously, its not as easy as it sounds to just drop in a 540 kit to a used 502. The pistons and rings need to be properly clearanced to the bores and on used bores that's not going to be practical or properly possible on your island less machines. Even if the rotating assemblies were prebalanced and you get lucky on crank and rod bearing clearances I think your heading for another thread on OSo about your future engine misfortunes. don't be penny wise and pound foolish!
You need engines in your boat that are turn key reliable and ready to run with correct parts, machining, assembly etc. My recommendation and serious suggestion to you based on your locale and situation is if your long blocks are not damaged beyond core credit is to exchange them for two new properly built marine 540 long blocks ready to bolt on your accessories and go. There are plenty of good marine engine builders here on OSO who can do these long blocks for you and if the freight for the return of the old blocks is more than the core charge, then just sell them on the island or use them for coffee tables, etc.
Just my professional opinion here not a lecture.
Good Luck,

Best Regards,
Ray @ Raylar

articfriends

iTrader: (1)

It would be the ultimate mail order challenge build,building motors on a island that has no dyno,engine tuners or even a machine shop but it could turn into one long, drawn out nightmare. Remember,the professor could create a chain reaction from coconuts but he couldn't patch the boat to get off the island or fix the radio to call for help ,Smitty

stevesxm

i understand completely and you are essentially correct. we'll just have to see what shakes out when it comes apart. interestingly enough, ocean freight TO here is very very reasonable... almost cheap. when i shipped over the two motors i bought to repower my boat 4 years ago, it was only
$ 250/ per motor out of miami. RETURN shipping to the US is a whole different ball bame for some reason. about 5 times as much plus the brokers fees etc that are required on the US side.. so the bottom line is that cores would be cost prohibitive to return.

when i retired here i brought all my tools and gages so clearencing the assemblies correctly wouldn't be a chore and flying in small bits is a common place deal.

if i was smart i might just get a quote on a couple of short blocks ... and see what that would entail but my feeling is that that cost would start to weigh heavily on this guy. these motors only have a couple hundred hours on them and have been well looked after so one of them is still fine and the other just has what, i believe , to require a simple straight forward repair. i was just daydreaming that a 540 upgrade while it was apart might have been an option. on paper i really liked the the achectecture of the 540 layout and with a nice clean injection i thing it would be a wonderful low reving, 50 or 60 hp upgrade for performance deep vee thats used for pleasure.

well... as i said... in a few days ill figure something out.

ray... just for the sake of discussion... SUPPOSE i had a couple of 540 piston kits delivered to you ( or bought them from you) ... how much would you charge me to take those pistons, clearence them into a pair of good usable gen 6 blocks you would sell me and crate them up for shipping ?

stevesxm

that's good... VERY VERY good. there are a couple of engine shops here but they are primarily into the " ship in full assys and replace mode ". the one guy that has 3 or 4 of these boats parked in front of his house and " builds" these motors has had the same 4 boats in front of his house for 4 years and when a motor does evententually emerge from his garage , blows up in fairly short order. he is also the local provider of moorings...
go figure

mrhorsepower1

I have a engine client in the British Virgin Islands that currently owns the Cigarette "Fat Boy".

stevesxm

well... if one of his motors disappears don't tell him about this thread

Pokher Ace

Im curious about this as well. I have the same motors that I will be pulling over the winter, and havent decided how crazy or conservative to go. Would like to know what kind of hp to expect in a 540- 502 mpi sleeper. At the minimum I was going to do cam, head work, and exhaust depending on inspection of lower end

stevesxm

my estimate for just the 540 kit was 50 hp. ateco makes a 540 long block , off the shelf, with their cam that they say make 620 if i remember correctly and that was around 5 grand or so.

oh... and i spoke to weisco , with whom i did business for years and who makes a great product, and they will make me pistons to go in a std bore 502 w/ the stroker crank w/ rings etc for about $ 800.